Alternative fuel system

ABSTRACT

An apparatus and a method are provided for an alternative fuel system, comprising a plurality of fuel tank assemblies interconnected with fuel lines; the plurality of fuel tank assemblies comprising a CNG fuel tank and a fuel tank shield; wherein a first and second fuel tank assembly is disposed immediately in front of a rear wheel assembly, and a third fuel tank assembly is disposed immediately behind the rear wheel assembly.

PRIORITY

This application claims the benefit of and priority to U.S. patentapplication Ser. No. 16/953,725 filed on Nov. 20, 2022 and U.S. patentapplication Ser. No. 15/721,807 filed Sep. 30, 2017, now issued U.S.Pat. No. 10,850,610 and U.S. Provisional Application, entitled “CNG FuelTank Architecture,” filed on Sep. 30, 2016 and having application Ser.No. 62/402,792.

FIELD

The field of the present disclosure generally relates to motor vehicles.More particularly, the field of the invention relates to a system and amethod for a vehicle chassis having alternative fuel tankslongitudinally disposed immediately in front and behind a rear wheelassembly.

BACKGROUND

A fuel tank is a safe container for flammable fluids, such as gasoline.Though any storage tank for fuel may be so called, the term is typicallyapplied to part of an engine system in which the fuel is stored andpropelled (fuel pump) or released (pressurized gas) into an engine. Fueltanks range in size and complexity from the small plastic tank of abutane lighter to multi-chambered designs.

The maximum distance a combustion-engine powered car with a full tankcan cover is the product of the tank capacity and its fuel efficiency(as in miles per gallon). While larger tanks increase the maximumdistance, they also take up more space and (especially when full) add tothe total weight, requiring higher fuel consumption for the sameperformance. Fuel-tank capacity is therefore the result of a trade-offin design considerations. For most compact cars, the capacity is in therange 12-17 US gallons. For safety considerations, in modern cars thefuel tank is usually located ahead of the rear axle, out of the crumplezones of the car.

As compared to their gasoline-powered counterparts, natural gas vehicles(NGVs) may offer an array of economic and environmental benefitsincluding low-cost, improving regional air quality, reducing greenhousegas emissions, thereby reducing our dependence on petroleum andproviding a pathway to a hydrogen economy.

Practically, however, NGVs have not been a perfect substitute forgasoline powered vehicles, because unlike liquid fuel, whichconsistently holds about the same volume of fuel across a broad range ofconditions, compressed natural gas (CNG), for example, can expand andcontract significantly depending on temperature. For example, underindustry standard conditions, a CNG tank on a vehicle may be able tohold 20 gasoline gallon equivalents, but on a hot day the gas willexpand and the tank may only fill to 75% (or less) of its potential.Thus, CNG vehicles may have a reduced driving range prior to refuelingas compared to their conventional fuel counterparts.

What is needed, therefore, is an alternative fuel system engineered tomaximize the design benefits of today's gasoline engines that can serveas a direct replacement for OEM gasoline injection systems for both CNGand propane fuel systems, while also operating within California AirResources Board (CARB) and U.S. Environmental Protection Agency (EPA)requirements. What is also needed is an alternative fuel system that isconfigured to increase a vehicle's range without adding excess weightand adversely affecting the vehicle's handling.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings refer to embodiments of the present disclosure in which:

FIG. 1A illustrates an isometric perspective view of the CNG fuel tankarchitecture;

FIG. 1B illustrates a side view of the CNG fuel tank architecture ofFIG. 1 ;

FIG. 2 illustrates an isometric perspective view of the CNG fuel tankarchitecture of FIG. 1 , when disposed with an exemplary vehiclechassis; and

FIG. 3 illustrates an isometric perspective view of an alternative CNGfuel tank architecture, when disposed with an exemplary vehicle chassis.

While the present disclosure is subject to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Theinvention should be understood to not be limited to the particular formsdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present disclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present disclosure. Itwill be apparent, however, to one of ordinary skill in the art that theinvention disclosed herein may be practiced without these specificdetails. The specific details may be varied from and still becontemplated to be within the spirit and scope of the presentdisclosure. The term “coupled” is defined as meaning connected eitherdirectly to the component or indirectly to the component through anothercomponent. Further, as used herein, the terms “about,” “approximately,”or “substantially” for any numerical values or ranges indicate asuitable dimensional tolerance that allows the part or collection ofcomponents to function for its intended purpose as described herein.

In general, the present disclosure describes an apparatus andcorresponding methods for an alternative fuel system with respect to amotor vehicle. The alternative fuel may be CNG, propane, or any otherfuel source without limitation. In the interest of brevity, the exampleof CNG is used in the embodiments described herein. It should beunderstood that the apparatus and methods described herein may beutilized so as to “convert” a gasoline-powered motor vehicle into analternative fuel-powered vehicle.

In one embodiment, a plurality of alternative fuel tanks are disposedlongitudinally, immediately about the rear-wheel assembly of a motorvehicle. Preferably, a plurality of CNG fuel tanks are disposed in aparallel and longitudinal fashion in front of the rear-wheel assembly,and oriented so as to be disposed immediately outside the centralchassis. Moreover, one or more CNG fuel tanks may be disposedimmediately behind the rear-wheel assembly, and inside the centralchassis.

In one embodiment, a compressed natural gas fuel system is disclosed,comprising a plurality of fuel tank assemblies interconnected with fuellines; the plurality of fuel tank assemblies comprising a CNG fuel tankand a fuel tank shield; wherein a first and second fuel tank assemblyare disposed immediately in front of a rear wheel assembly, and a thirdfuel tank assembly disposed immediately behind the rear wheel assembly.

In one embodiment, the third fuel tank assembly is disposedlongitudinally between the rear wheels of a vehicle. In yet anotheraspect, the first and second fuel tank assemblies are disposedlongitudinally in line with the rear wheels of the vehicle.

In one embodiment, the third fuel tank assembly comprises a plurality ofCNG fuel tanks. In another embodiment, the fuel lines couple a defuelingassembly with a bulkhead. In yet another embodiment, the high pressurefill and check valve assembly is coupled to the bulkhead and fuel lines.In one embodiment, the check valve assembly is configured to provideunidirectional flow of CNG so as to prevent sudden backflow ofpressurized natural gas. In another embodiment, caged structures aredisposed around the first and second CNG fuel tanks.

In another embodiment, a method of converting a gasoline-powered motorvehicle to a natural gas vehicle is described comprising: reviewing thechassis and body specifications of the motor vehicle so as to ensureoptimal system integration; optimizing the design and layout of analternative fuel system to match a customer specification; removing anOEM fuel system; installing a plurality of fuel tanks configured tohouse a natural gas and corresponding high and low pressure fuel lines;installation of safety equipment, where the safety equipment comprisesone or more gravel shields configured to protect the fuel tanks; andperforming at least a first diagnostic test of the fuel system to ensureproper drivability.

FIG. 1A illustrates an isometric perspective view of the CNG fuel tankarchitecture according to one embodiment. As shown, a plurality of CNGfuel tanks 105 are each disposed in a fuel tank shield 110. In oneembodiment, the CNG fuel tanks 105 are configured so as to have a CNGfueling system pressure of substantially 3,600 psi. It should beunderstood that in various embodiments, the fueling system pressure maybe substantially 3,000 psi, or any other pressure rating withoutlimitation. It is envisioned that the CNG fuel tanks 105 are configuredto hold up to 125% of their operating pressure. Thus, a 3,000 psi tankmay be filled to 3,750 psi and a 3,600 tank can be filled to 4,500 psi.Consequently, this extra capacity makes it possible to fill the tanks105 to a higher pressure on hot days when the gas is expanding, as wellas compensate for the heat of recompression. The CNG fuel tanks 105 maybe made of any material, including without limitation aluminum, steel,carbon fiber, and the like.

The fuel tank shields 110 are configured so as to add an extra layer ofprotection to the CNG fuel tanks 105. In one embodiment, the fuel tankshields 110 feature high-density, cross linked polyethylene, so as todissipate stress and impact from gravel, for example. It is envisionedthat the fuel tank shields 110 are resistant to extremely hot and coldtemperatures. Preferably, the fuel tank shields 110 are constructed fromhighly strong yet light weight material, so as to not materially affectthe handling characteristics of the vehicle. In one embodiment, the fueltank shields 110 feature a substantially cylindrical shape with aprominent cavity so that the CNG fuel tanks 105 may each be disposedtherein. It should be understood that the fuel tank shields 110 may becoupled with various straps, brackets 111, and the like so as to matewith the chassis of the motor vehicle, without limitation. In oneembodiment, for example, fuel tank straps 112 are configured to retainthe CNG fuel tanks 105 within the fuel tank shields 110.

In embodiments, the fuel tank shields 110 may be coupled with asupplemental heat shield 115, with the specific purpose of preventingexcess heat from effecting the capacity of the CNG fuel tanks 105. Inone embodiment, the supplement heat shield 115 is substantially planar,and may be comprised of a substantially metallic material. Similarly, itis envisioned that one or more layers of woven silica with a flexiblealuminized finish may be disposed on the heat shield 115.

In embodiments, a method of converting a gasoline-powered motor vehicleis described, including the steps of reviewing the chassis and bodyspecifications of the motor vehicle so as to ensure optimal systemintegration; optimizing the design and layout of the new fuel system tomatch a customer specification; removal of an OEM fuel system;installation of a plurality of cylinders configured to house a gas suchas CNG; installation of high and low pressure fuel lines to providecomplete vehicle reliability; installation of safety equipment, wherethe safety equipment comprises one or more gravel shields configured toprotect fuel tanks; and at least a first diagnostic test of the fuelsystem to ensure proper drivability.

As shown in FIG. 1A, the CNG fuel tanks 105 may be interconnected usinga plurality of fuel lines 125. In one embodiment, a defueling assembly130 is disposed near the rear-most CNG fuel tank 107. It should beunderstood that the defueling assembly 130 is configured so as to safelyremove CNG from the CNG fuel tanks 105 prior to servicing the CNGvehicle, for example. The CNG that is removed from the tanks may berouted in any of various ways, including for example, suction via acompressor, pipeline, other low pressure natural gas system or it may beatmospherically vented. In one embodiment, fuel lines 125 couple thedefueling assembly 130 with bulkhead 135.

A high pressure fill and check valve assembly 140 is coupled to thebulkhead 135, and fuel lines 125. It should be understood that the exactplacement of the check valve assembly 140 may be varied. In embodiments,more than one check valve assembly 140 may be utilized. In oneembodiment, the check valve assembly 140 is configured so as to provideuni-directional flow of CNG and can prevent sudden backflow ofpressurized natural gas. A large variety of end connections such asfemale BSP threads and tube fittings may be utilized, withoutlimitation. Also, as shown in FIG. 1 , an in-line filter 145 is coupledbetween the plurality of CNG fuel tank assemblies 106-108 and a gasregulator 150 using the fuel lines 125. In one embodiment, the in-linefilter 145 is configured so as to remove particulates and otherundesirable debris from the fueling system 100. In one embodiment, thegas regulator 150 is configured to automatically cuts off the flow ofCNG at a predetermined pressure level.

FIG. 1B illustrates a side perspective view of the CNG tank architectureof FIG. 1 . As shown, a key aspect of the embodiments described hereinis the specific layout of the CNG fuel tank architecture 100. FIG. 2illustrates an exemplary chassis 200, and the CNG fuel tank architecture10. In one embodiment, the fuel tank assemblies 106, 108 are disposed ina longitudinal fashion immediately in front of the rear wheel assembly210. Similarly, the fuel tank assembly 107 is disposed in the middle ofthe chassis 200, immediately behind the rear wheel assembly 210. Itshould be understood that such an arrangement provides superior weightdistribution and balance with respect to the chassis' suspensiongeometry.

In one embodiment, each of the fuel tank assemblies 106-108 may be ofsubstantially the same size, weight, and capacity. In one embodiment,the fuel tank assemblies 106 and 108 have substantially the samedimensions, but the fuel tank assembly 107 may be smaller or larger bycomparison. It should be understood that the precise location of thefuel tank assembly 107 may be varied without limitation, depending onthe application. Thus, it is envisioned that the fuel tank assembly 107may be disposed directly in between the rear wheels of the rear wheelassembly, or partially overlap the rear wheel assembly, withoutlimitation. Similarly, the fuel tank assemblies 106-108 may be disposedin various locations with respect to the chassis 200, depending on theapplication. In some instances, it may be beneficial to mount varioussizes of CNG fuel tanks 105 in locations that are less likely to beeffected by the vehicle's ground clearance, suspension geometry, and thelike, without limitation.

FIG. 3 illustrates an isometric perspective view of a CNG fuel tankarchitecture which is substantially similar to the structure shown inFIG. 2 . As shown, in one embodiment, caged structures 305 are disposedaround the CNG fuel tanks 105. Although not shown, fuel tank shields 110may also be used. In one embodiment, the caged structures 305 feature anexoskeleton formed of substantially metallic elements. Morespecifically, the structures 305 comprise a plurality of verticallydisposed members 310 that may be welded and/or otherwise adhered tocross-members 315. Also, as shown in FIG. 3 , the fuel tank assembly 107features a plurality of CNG fuel tanks 105. It should be understood thateach of the fuel tank assemblies 106-108 may feature one or more CNGfuel tanks 105 depending on the end use or application. For example, asshown in FIG. 4 , CNG fuel tanks 105 may be stacked in a longitudinalmanner so as to further increase CNG holding capacity, and thereforeadvantageously increase driving range of the vehicle.

While the invention has been described in terms of particular variationsand illustrative figures, those of ordinary skill in the art willrecognize that the invention is not limited to the variations or figuresdescribed. In addition, where methods and steps described above indicatecertain events occurring in certain order, those of ordinary skill inthe art will recognize that the ordering of certain steps may bemodified and that such modifications are in accordance with thevariations of the invention. Additionally, certain of the steps may beperformed concurrently in a parallel process when possible, as well asperformed sequentially as described above. To the extent there arevariations of the invention, which are within the spirit of thedisclosure or equivalent to the inventions found in the claims, it isthe intent that this patent will cover those variations as well.Therefore, the present disclosure is to be understood as not limited bythe specific embodiments described herein, but only by scope of theappended claims.

What is claimed:
 1. An alternative fuel system, comprising: a pluralityof fuel tank assemblies interconnected with fuel lines; the plurality offuel tank assemblies comprising a CNG fuel tank and a fuel tank shield;wherein a first and second fuel tank assembly is disposed immediately infront of a rear wheel assembly, and a third fuel tank assembly isdisposed immediately behind the rear wheel assembly.
 2. The alternativefuel system of claim 1, wherein the third fuel tank assembly is disposedlongitudinally between the rear wheels of a vehicle.
 3. The alternativefuel system of claim 1, wherein the first and second fuel tankassemblies are disposed longitudinally in line with the rear wheels ofthe vehicle.
 4. The alternative fuel system of claim 1, wherein thethird fuel tank assembly comprises a plurality of CNG fuel tanks.
 5. Thealternative fuel system of claim 1, wherein the fuel lines couple adefueling assembly with a bulkhead.
 6. The alternative fuel system ofclaim 5, wherein a high pressure fill and check valve assembly iscoupled to the bulkhead and fuel lines.
 7. The alternative fuel systemof claim 6, wherein the check valve assembly is configured to provideunidirectional flow of CNG so as to prevent sudden backflow ofpressurized natural gas.
 8. The alternative fuel system of claim 1,wherein caged structures are disposed around the first and second CNGfuel tanks.
 9. A method of converting a gasoline-powered motor vehicleto a natural gas vehicle, comprising: reviewing the chassis and bodyspecifications of the motor vehicle so as to ensure optimal systemintegration; optimizing the design and layout of an alternative fuelsystem to match a customer specification; removing an OEM fuel system;installing a plurality of fuel tanks configured to house a natural gasand corresponding high and low pressure fuel lines; installation ofsafety equipment, where the safety equipment comprises one or moregravel shields configured to protect the fuel tanks; and performing atleast a first diagnostic test of the fuel system to ensure properdrivability.